<?php

class StrictFileReader {
	private $f;
	private $buf = '', $off = 0;

	public function __construct($file_name) {
		$this->f = fopen($file_name, 'r');
	}

	public function failed() {
		return $this->f === false;
	}

	public function readChar() {
		if (isset($this->buf[$this->off])) {
			return $this->buf[$this->off++];
		}
		return fgetc($this->f);
	}
	public function unreadChar($c) {
		$this->buf .= $c;
		if ($this->off > 1000) {
			$this->buf = substr($this->buf, $this->off);
			$this->off = 0;
		}
	}

	public function readString() {
		$str = '';
		while (true) {
			$c = $this->readChar();
			if ($c === false) {
				break;
			} elseif ($c === " " || $c === "\n" || $c === "\r") {
				$this->unreadChar($c);
				break;
			} else {
				$str .= $c;
			}
		}
		return $str;
	}

	public function readLine() {
		$str = '';
		while (true) {
			$c = $this->readChar();
			if ($c === false) {
				break;
			} elseif ($c === "\n") {
				break;
			} else {
				$str .= $c;
			}
		}
		return $str;
	}

	public function ignoreWhite() {
		while (true) {
			$c = $this->readChar();
			if ($c === false) {
				break;
			} elseif ($c === " " || $c === "\n" || $c === "\r") {
				continue;
			} else {
				$this->unreadChar($c);
				break;
			}
		}
	}

	public function eof() {
		return feof($this->f);
	}

	public function close() {
		fclose($this->f);
	}
}